This Specialized Center of Research in Pulmonary Diseases is engaged in a long term multi-disciplinary project designed to study the evolution and natural history of obstructive lung disorders such as asthma, bronchitis, and emphysema. A longitudinal epidemiological study is being carried out on a stratified random sample of households and subsamples of subjects are being identified for special detailed studies. Data are being obtained in regard to: A) Early detection of the diseases; B) Importance of genetic factors, including alpha1-antitrypsin deficiency; C) Relationship of childhood respiratory infections and atopic asthma to development of chronic disease; D) Mechanisms for development of airways obstruction and its relationship to anatomical and radiographic changes; E) Influence of environmental and social factors on the disorder; and F) Development of cardiovascular abnormalities. Laboratory subprojects include special post-mortem physiological and morphological studies, studies of dynamic properties of respiratory airways, and physiological and biochemical studies concerning respiratory and vascular effects of fibrinopeptides, specific relationships of surface active material to respiratory distress syndromes, and development of pulmonary oxygen toxicity.